Royal Blue (#4169E1) is a medium, moderately saturated blue hue. Royal blue is a deep, vivid blue said to have been created for Queen Charlotte's dress.
In RGB it is made of 65 red, 105 green and 225 blue. Its HSL hue angle is 225° with 73% saturation and 57% lightness, while its perceptual OKLCH lightness is 56% with a chroma of 0.188. For print, a starting CMYK mix is 71% cyan, 53% magenta, 0% yellow and 12% black.
As a text color on white, Royal Blue has a contrast ratio of 4.85:1, which passes WCAG AA for normal text. On black it reaches 4.33:1 and passes AA only for large text. If you use Royal Blue as a background, put white text on it. The APCA lightness contrast is Lc 31 for black text and Lc -79 for white text.
Its perceptual complement is #926F00, close to caramel. Colors that look most similar are azure, denim, sapphire. It looks fairly similar to people with red-green color blindness (ΔE 3), so its meaning mostly survives.